Fix warning: Add ThreadHelper.ThrowIfNotOnUIThread();

Change-Id: I8e7cc3a16eb5b303823ea5b1c85e04f5ce85947b
Reviewed-by: Miguel Costa <miguel.costa@qt.io>

16 files changed, 425 insertions, 41 deletions

diff --git a/QtVsTools.Core/HelperFunctions.cs b/QtVsTools.Core/HelperFunctions.cs
index 1327a864..df92470b 100644
--- a/QtVsTools.Core/HelperFunctions.cs
+++ b/QtVsTools.Core/HelperFunctions.cs
@@ -27,6 +27,7 @@
 ****************************************************************************/
 
 using EnvDTE;
+using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.VCProjectEngine;
 #if VS2017
 using Microsoft.Win32;
@@ -95,16 +96,19 @@ namespace QtVsTools.Core
 
         static public void SetDebuggingEnvironment(Project prj)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             SetDebuggingEnvironment(prj, string.Empty);
         }
 
         static public void SetDebuggingEnvironment(Project prj, string solutionConfig)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             SetDebuggingEnvironment(prj, "PATH=$(QTDIR)\\bin;$(PATH)", false, solutionConfig);
         }
 
         static public void SetDebuggingEnvironment(Project prj, string envpath, bool overwrite)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             SetDebuggingEnvironment(prj, envpath, overwrite, string.Empty);
         }
 
@@ -113,6 +117,8 @@ namespace QtVsTools.Core
             if (QtProject.GetFormatVersion(prj) >= Resources.qtMinFormatVersion_Settings)
                 return;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             // Get platform name from given solution configuration
             // or if not available take the active configuration
             var activePlatformName = string.Empty;
@@ -174,8 +180,9 @@ namespace QtVsTools.Core
 
         public static bool IsProjectInSolution(DTE dteObject, string fullName)
         {
-            var fi = new FileInfo(fullName);
+            ThreadHelper.ThrowIfNotOnUIThread();
 
+            var fi = new FileInfo(fullName);
             foreach (var p in ProjectsInSolution(dteObject)) {
                 if (p.FullName.ToLower() == fi.FullName.ToLower())
                     return true;
@@ -336,6 +343,8 @@ namespace QtVsTools.Core
         /// <returns></returns>
         public static void ReplaceInCustomBuildTools(Project project, string oldString, string replaceString)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var vcPro = (VCProject)project.Object;
             if (vcPro == null)
                 return;
@@ -410,6 +419,8 @@ namespace QtVsTools.Core
         /// <param name="projectItem">Project Item which needs to have custom build tool</param>
         static public void EnsureCustomBuildToolAvailable(ProjectItem projectItem)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             foreach (Property prop in projectItem.Properties) {
                 if (prop.Name == "ItemType") {
                     if ((string)prop.Value != "CustomBuild")
@@ -447,7 +458,8 @@ namespace QtVsTools.Core
             if (QtProject.GetFormatVersion(project) >= Resources.qtMinFormatVersion_Settings)
                 return;
 
-            string qtDir = null;
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var vcPro = (VCProject)project.Object;
             if (!IsQMakeProject(project))
                 return;
@@ -455,7 +467,7 @@ namespace QtVsTools.Core
                 // TODO: qtPro is never used.
                 var qtPro = QtProject.Create(project);
                 var vm = QtVersionManager.The();
-                qtDir = vm.GetInstallPath(project);
+                string qtDir = vm.GetInstallPath(project);
 
                 foreach (var global in (string[])project.Globals.VariableNames) {
                     if (global.StartsWith("Qt5Version", StringComparison.Ordinal))
@@ -485,7 +497,7 @@ namespace QtVsTools.Core
 
                 ReplaceInCustomBuildTools(project, "$(QTDIR)", qtDir);
             } else {
-                qtDir = GetQtDirFromQMakeProject(project);
+                string qtDir = GetQtDirFromQMakeProject(project);
 
                 var vm = QtVersionManager.The();
                 var qtVersion = vm.GetQtVersionFromInstallDir(qtDir);
@@ -558,6 +570,8 @@ namespace QtVsTools.Core
         /// <param name="project">The project is needed to convert relative paths to absolute paths.</param>
         private static void ReplaceDirectory(ref List<string> paths, string oldDirectory, string replacement, Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             for (var i = 0; i < paths.Count; ++i) {
                 var dirName = paths[i];
                 if (dirName.StartsWith("\"", StringComparison.Ordinal) && dirName.EndsWith("\"", StringComparison.Ordinal)) {
@@ -582,6 +596,8 @@ namespace QtVsTools.Core
 
         public static string GetQtDirFromQMakeProject(Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var vcProject = project.Object as VCProject;
             if (vcProject == null)
                 return null;
@@ -674,6 +690,8 @@ namespace QtVsTools.Core
             if (QtProject.GetFormatVersion(proj) >= Resources.qtMinFormatVersion_Settings)
                 return true;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var envPro = proj.Object as Project;
             if (envPro.Globals == null || envPro.Globals.VariableNames == null)
                 return false;
@@ -691,6 +709,7 @@ namespace QtVsTools.Core
         /// <param name="proj">project</param>
         public static bool IsQtProject(Project proj)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             try {
                 if (proj != null && proj.Kind == "{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}")
                     return IsQtProject(proj.Object as VCProject);
@@ -723,6 +742,7 @@ namespace QtVsTools.Core
         /// <param name="proj">project</param>
         public static bool IsQMakeProject(Project proj)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             try {
                 if (proj != null && proj.Kind == "{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}")
                     return IsQMakeProject(proj.Object as VCProject);
@@ -732,6 +752,8 @@ namespace QtVsTools.Core
 
         public static void CleanupQMakeDependencies(Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var vcPro = (VCProject)project.Object;
             // clean up qmake mess
             var rxp1 = new Regex("\\bQt\\w+d?5?\\.lib\\b");
@@ -904,6 +926,8 @@ namespace QtVsTools.Core
             if (string.IsNullOrEmpty(nodeToCollapseFilter))
                 return;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             foreach (UIHierarchyItem innerItem in item.UIHierarchyItems) {
                 if (innerItem.Name == nodeToCollapseFilter)
                     CollapseFilter(innerItem, hierarchy);
@@ -914,6 +938,8 @@ namespace QtVsTools.Core
 
         public static void CollapseFilter(UIHierarchyItem item, UIHierarchy hierarchy)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var subItems = item.UIHierarchyItems;
             if (subItems != null) {
                 foreach (UIHierarchyItem innerItem in subItems) {
@@ -962,7 +988,7 @@ namespace QtVsTools.Core
 
         public static List<string> GetProjectFiles(Project pro, FilesToList filter)
         {
-            var fileList = new List<string>();
+            ThreadHelper.ThrowIfNotOnUIThread();
 
             VCProject vcpro;
             try {
@@ -972,6 +998,7 @@ namespace QtVsTools.Core
                 return null;
             }
 
+            var fileList = new List<string>();
             var configurationName = pro.ConfigurationManager.ActiveConfiguration.ConfigurationName;
 
             foreach (VCFile vcfile in (IVCCollection)vcpro.Files) {
@@ -1040,6 +1067,8 @@ namespace QtVsTools.Core
         /// <param name="fileName"></param>
         public static void RemoveFileInProject(VCProject vcpro, string fileName)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var qtProj = QtProject.Create(vcpro);
             var fi = new FileInfo(fileName);
 
@@ -1055,6 +1084,9 @@ namespace QtVsTools.Core
         {
             if (dteObject == null)
                 return null;
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             Array prjs = null;
             try {
                 prjs = (Array)dteObject.ActiveSolutionProjects;
@@ -1073,6 +1105,8 @@ namespace QtVsTools.Core
 
         public static Project GetActiveDocumentProject(DTE dteObject)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (dteObject == null)
                 return null;
             var doc = dteObject.ActiveDocument;
@@ -1087,6 +1121,8 @@ namespace QtVsTools.Core
 
         public static Project GetSingleProjectInSolution(DTE dteObject)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var projectList = ProjectsInSolution(dteObject);
             if (dteObject == null || dteObject.Solution == null ||
                     projectList.Count != 1)
@@ -1102,6 +1138,8 @@ namespace QtVsTools.Core
         /// </summary>
         public static Project GetSelectedQtProject(DTE dteObject)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             // can happen sometimes shortly after starting VS
             if (dteObject == null || dteObject.Solution == null
                 || ProjectsInSolution(dteObject).Count == 0)
@@ -1121,6 +1159,8 @@ namespace QtVsTools.Core
             if (GetSelectedQtProject(dteObject) == null)
                 return null;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (dteObject.SelectedItems.Count <= 0)
                 return null;
 
@@ -1159,6 +1199,8 @@ namespace QtVsTools.Core
 
         public static RccOptions ParseRccOptions(string cmdLine, VCFile qrcFile)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var pro = VCProjectToProject((VCProject)qrcFile.project);
 
             var rccOpts = new RccOptions(pro, qrcFile);
@@ -1181,11 +1223,14 @@ namespace QtVsTools.Core
 
         public static Project VCProjectToProject(VCProject vcproj)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             return (Project)vcproj.Object;
         }
 
         public static List<Project> ProjectsInSolution(DTE dteObject)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var projects = new List<Project>();
             var solution = dteObject.Solution;
             if (solution != null) {
@@ -1207,6 +1252,8 @@ namespace QtVsTools.Core
 
         private static void addSubProjects(Project prj, ref List<Project> projects)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             // If the actual object of the project is null then the project was probably unloaded.
             if (prj.Object == null)
                 return;
@@ -1226,6 +1273,8 @@ namespace QtVsTools.Core
             if (subItems == null)
                 return;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             foreach (ProjectItem item in subItems) {
                 Project subprj = null;
                 try {
@@ -1358,13 +1407,14 @@ namespace QtVsTools.Core
             string platformName,
             string filePath = null)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (project == null
                 || string.IsNullOrEmpty(configName)
                 || string.IsNullOrEmpty(platformName))
                 return false;
 
             var vcProject = project.Object as VCProject;
-
             if (filePath == null) {
                 var vcConfig = (from VCConfiguration _config
                                 in (IVCCollection)vcProject.Configurations
@@ -1620,6 +1670,8 @@ namespace QtVsTools.Core
 
         public static bool SetVCVars(VersionInformation VersionInfo, ProcessStartInfo startInfo)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (VersionInfo == null) {
                 VersionInfo = QtVersionManager.The().GetVersionInfo(
                     QtVersionManager.The().GetDefaultVersion());
diff --git a/QtVsTools.Core/MainWinWrapper.cs b/QtVsTools.Core/MainWinWrapper.cs
index f8beb439..2880bd06 100644
--- a/QtVsTools.Core/MainWinWrapper.cs
+++ b/QtVsTools.Core/MainWinWrapper.cs
@@ -44,6 +44,8 @@ namespace QtVsTools.Core
         {
             get
             {
+                Microsoft.VisualStudio.Shell.ThreadHelper.ThrowIfNotOnUIThread();
+
                 if (dteObject != null)
 #if VS2022
                     return dteObject.MainWindow.HWnd;
diff --git a/QtVsTools.Core/Messages.cs b/QtVsTools.Core/Messages.cs
index 7eb46ab0..c00208d6 100644
--- a/QtVsTools.Core/Messages.cs
+++ b/QtVsTools.Core/Messages.cs
@@ -31,11 +31,14 @@ using System.Collections.Concurrent;
 using System.Diagnostics;
 using System.Linq;
 using System.Threading;
-using Thread = System.Threading.Thread;
 using System.Windows.Forms;
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.Threading;
 using QtVsTools.VisualStudio;
+using Microsoft.VisualStudio.Shell;
+
+using Thread = System.Threading.Thread;
+using Task = System.Threading.Tasks.Task;
 
 namespace QtVsTools.Core
 {
@@ -49,8 +52,13 @@ namespace QtVsTools.Core
         {
             get
             {
+                ThreadHelper.ThrowIfNotOnUIThread();
                 return _BuildPane ?? (_BuildPane = Window.OutputWindowPanes.Cast<OutputWindowPane>()
-                    .Where(pane => pane.Guid == "{1BD8A850-02D1-11D1-BEE7-00A0C913D1F8}")
+                    .Where(pane =>
+                    {
+                        ThreadHelper.ThrowIfNotOnUIThread();
+                        return pane.Guid == "{1BD8A850-02D1-11D1-BEE7-00A0C913D1F8}";
+                    })
                     .FirstOrDefault());
             }
         }
@@ -66,11 +74,14 @@ namespace QtVsTools.Core
                 Text = text,
                 Activate = activate
             });
+
+            ThreadHelper.ThrowIfNotOnUIThread();
             FlushMessages();
         }
 
         static void OutputWindowPane_Print(string text)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             OutputWindowPane_Init();
             Pane.OutputString(text + "\r\n");
             // show buildPane if a build is in progress
@@ -87,12 +98,17 @@ namespace QtVsTools.Core
             {
                 Activate = true
             });
+
+            ThreadHelper.ThrowIfNotOnUIThread();
             FlushMessages();
         }
 
         static void OutputWindowPane_Activate()
         {
             OutputWindowPane_Init();
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             Pane?.Activate();
         }
 
@@ -155,12 +171,18 @@ namespace QtVsTools.Core
             {
                 Clear = true
             });
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             FlushMessages();
         }
 
         static void OutputWindowPane_Clear()
         {
             OutputWindowPane_Init();
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             Pane?.Clear();
         }
 
@@ -185,6 +207,9 @@ namespace QtVsTools.Core
             if (Dte == null)
                 Dte = VsServiceProvider.GetService<DTE>();
             var t = Stopwatch.StartNew();
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             while (Pane == null && t.ElapsedMilliseconds < 5000) {
                 try {
                     Window = Dte.Windows.Item(Constants.vsWindowKindOutput).Object as OutputWindow;
diff --git a/QtVsTools.Core/MsBuildProject.cs b/QtVsTools.Core/MsBuildProject.cs
index 83b0cda0..187382a2 100644
--- a/QtVsTools.Core/MsBuildProject.cs
+++ b/QtVsTools.Core/MsBuildProject.cs
@@ -39,6 +39,7 @@ using Microsoft.Build.Construction;
 using Microsoft.Build.Execution;
 using Microsoft.Build.Evaluation;
 using QtVsTools.SyntaxAnalysis;
+using Microsoft.VisualStudio.Shell;
 
 namespace QtVsTools.Core
 {
@@ -288,6 +289,8 @@ namespace QtVsTools.Core
         /// <returns>true if successful</returns>
         public bool UpdateProjectFormatVersion()
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (ConfigCondition == null)
                 return false;
 
@@ -910,6 +913,9 @@ namespace QtVsTools.Core
 
             var projPath = this[Files.Project].filePath;
             bool error = false;
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             using (var evaluator = new MSBuildEvaluator(this[Files.Project])) {
                 foreach (var row in query) {
 
@@ -1202,6 +1208,8 @@ namespace QtVsTools.Core
             //remove .moc.cbt CustomBuild items
             cbtToRemove.ForEach(x => x.Remove());
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             //convert moc custom build steps
             var mocCustomBuilds = GetCustomBuilds(QtMoc.ToolExecName);
             if (!SetCommandLines(qtMsBuild, configurations, mocCustomBuilds,
diff --git a/QtVsTools.Core/ProjectExporter.cs b/QtVsTools.Core/ProjectExporter.cs
index df8b7105..55d8c36e 100644
--- a/QtVsTools.Core/ProjectExporter.cs
+++ b/QtVsTools.Core/ProjectExporter.cs
@@ -28,6 +28,7 @@
 
 using EnvDTE;
 using EnvDTE80;
+using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.VCProjectEngine;
 using System;
 using System.Collections;
@@ -94,6 +95,8 @@ namespace QtVsTools.Core
             ProFileContent content;
             var prosln = new ProSolution(sln);
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             foreach (var proj in HelperFunctions.ProjectsInSolution(sln.DTE)) {
                 try {
                     // only add qt projects
@@ -113,6 +116,8 @@ namespace QtVsTools.Core
 
         private void addProjectsInFolder(Project solutionFolder, ProSolution sln)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             foreach (ProjectItem pi in solutionFolder.ProjectItems) {
                 var containedProject = pi.Object as Project;
                 if (HelperFunctions.IsQtProject(containedProject)) {
@@ -130,6 +135,8 @@ namespace QtVsTools.Core
             var qtPro = QtProject.Create(project);
             var content = new ProFileContent(qtPro.VCProject);
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             // hack to get active config
             var activeConfig = project.ConfigurationManager.ActiveConfiguration.ConfigurationName;
             var activePlatform = project.ConfigurationManager.ActiveConfiguration.PlatformName;
@@ -343,6 +350,8 @@ namespace QtVsTools.Core
 
         private static ProFileContent CreatePriFileContent(Project project, string priFileDirectory)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             ProFileOption option;
             var qtPro = QtProject.Create(project);
             var content = new ProFileContent(qtPro.VCProject);
@@ -432,6 +441,8 @@ namespace QtVsTools.Core
 
             qtDir = HelperFunctions.NormalizeRelativeFilePath(qtDir);
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             foreach (var s in includePaths.Split(';', ',')) {
                 var d = HelperFunctions.NormalizeRelativeFilePath(s);
                 if (!d.StartsWith("$(qtdir)\\include", StringComparison.OrdinalIgnoreCase) &&
@@ -461,9 +472,10 @@ namespace QtVsTools.Core
                 qtDir = Environment.GetEnvironmentVariable("QTDIR");
             if (qtDir == null)
                 qtDir = "";
-
             qtDir = HelperFunctions.NormalizeRelativeFilePath(qtDir);
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (paths != null) {
                 foreach (var s in paths.Split(';', ',')) {
                     var d = HelperFunctions.NormalizeRelativeFilePath(s);
@@ -491,6 +503,8 @@ namespace QtVsTools.Core
 
         private static void AddModules(QtProject qtPrj, ProFileOption optionQT, ProFileOption optionCONFIG)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             foreach (var module in QtModules.Instance.GetAvailableModules()) {
                 if (!qtPrj.HasModule(module.Id))
                     continue;
@@ -504,6 +518,8 @@ namespace QtVsTools.Core
 
         private void WriteProSolution(ProSolution prosln, bool openFile)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var sln = prosln.ProjectSolution;
             if (string.IsNullOrEmpty(sln.FileName))
                 return;
@@ -605,8 +621,8 @@ namespace QtVsTools.Core
                 WriteProFileOptions(sw, content.Options);
             }
 
-            // open the file in vs
-            if (openFile)
+            ThreadHelper.ThrowIfNotOnUIThread();
+            if (openFile) // open the file in vs
                 dteObject.OpenFile(Constants.vsViewKindTextView, proFile).Activate();
         }
 
@@ -714,6 +730,8 @@ namespace QtVsTools.Core
             foreach (var s in projFiles)
                 cmpProjFiles.Add(HelperFunctions.NormalizeFilePath(s).ToLower());
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var qtPro = QtProject.Create(vcproj);
             var filterPathTable = new Hashtable(17);
             var pathFilterTable = new Hashtable(17);
@@ -779,7 +797,7 @@ namespace QtVsTools.Core
 
         public void ExportToProFile()
         {
-            var expDlg = new ExportProjectDialog();
+            ThreadHelper.ThrowIfNotOnUIThread();
 
             var sln = dteObject.Solution;
             var prosln = CreateProFileSolution(sln);
@@ -789,6 +807,7 @@ namespace QtVsTools.Core
                 return;
             }
 
+            var expDlg = new ExportProjectDialog();
             expDlg.ProFileSolution = prosln;
             expDlg.StartPosition = FormStartPosition.CenterParent;
             var ww = new MainWinWrapper(dteObject);
@@ -814,8 +833,9 @@ namespace QtVsTools.Core
 
         public string ExportToPriFile(Project proj)
         {
-            VCProject vcproj;
+            ThreadHelper.ThrowIfNotOnUIThread();
 
+            VCProject vcproj;
             if (HelperFunctions.IsQtProject(proj)) {
                 try {
                     vcproj = (VCProject)proj.Object;
@@ -844,8 +864,9 @@ namespace QtVsTools.Core
 
         public void ExportToPriFile(Project proj, string fileName)
         {
-            var priFile = new FileInfo(fileName);
+            ThreadHelper.ThrowIfNotOnUIThread();
 
+            var priFile = new FileInfo(fileName);
             var content = CreatePriFileContent(proj, priFile.DirectoryName);
             WritePriFile(content, priFile.FullName);
         }
diff --git a/QtVsTools.Core/ProjectImporter.cs b/QtVsTools.Core/ProjectImporter.cs
index c9885d7a..ea72953f 100644
--- a/QtVsTools.Core/ProjectImporter.cs
+++ b/QtVsTools.Core/ProjectImporter.cs
@@ -27,6 +27,7 @@
 ****************************************************************************/
 
 using EnvDTE;
+using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.VCProjectEngine;
 using System;
 using System.Collections.Generic;
@@ -56,6 +57,8 @@ namespace QtVsTools.Core
             if (DialogResult.OK != toOpen.ShowDialog())
                 return;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var mainInfo = new FileInfo(toOpen.FileName);
             if (HelperFunctions.IsSubDirsFile(mainInfo.FullName)) {
                 // we use the safe way. Make the user close the existing solution manually
@@ -84,6 +87,8 @@ namespace QtVsTools.Core
                 return;
             ImportQMakeSolution(VCInfo, versionInfo);
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             try {
                 if (CheckQtVersion(versionInfo)) {
                     dteObject.Solution.Open(VCInfo.FullName);
@@ -113,6 +118,7 @@ namespace QtVsTools.Core
 
             ImportQMakeProject(VCInfo, versionInfo);
 
+            ThreadHelper.ThrowIfNotOnUIThread();
             try {
                 if (CheckQtVersion(versionInfo)) {
                     // no need to add the project again if it's already there...
@@ -179,6 +185,9 @@ namespace QtVsTools.Core
         private void ImportQMakeSolution(FileInfo solutionFile, VersionInformation vi)
         {
             var projects = ParseProjectsFromSolution(solutionFile);
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             foreach (var project in projects) {
                 var projectInfo = new FileInfo(project);
                 ImportQMakeProject(projectInfo, vi);
@@ -205,6 +214,8 @@ namespace QtVsTools.Core
 
         private void ImportQMakeProject(FileInfo projectFile, VersionInformation vi)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var xmlProject = MsBuildProject.Load(projectFile.FullName);
             xmlProject.ReplacePath(vi.qtDir, "$(QTDIR)");
             xmlProject.ReplacePath(projectFile.DirectoryName, ".");
@@ -241,6 +252,7 @@ namespace QtVsTools.Core
             qtProject.CollapseFilter(Filters.ResourceFiles().Name);
             qtProject.CollapseFilter(Filters.GeneratedFiles().Name);
 
+            ThreadHelper.ThrowIfNotOnUIThread();
             try {
                 // save the project after modification
                 qtProject.Project.Save(null);
@@ -249,6 +261,8 @@ namespace QtVsTools.Core
 
         private FileInfo RunQmake(FileInfo mainInfo, string ext, bool recursive, VersionInformation vi)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var name = mainInfo.Name.Remove(mainInfo.Name.IndexOf('.'));
 
             var VCInfo = new FileInfo(mainInfo.DirectoryName + "\\" + name + ext);
diff --git a/QtVsTools.Core/QMake.cs b/QtVsTools.Core/QMake.cs
index 07101389..7ea1be88 100644
--- a/QtVsTools.Core/QMake.cs
+++ b/QtVsTools.Core/QMake.cs
@@ -31,6 +31,7 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
 using System.Text;
+using Microsoft.VisualStudio.Shell;
 using QtVsTools.VisualStudio;
 
 namespace QtVsTools.Core
@@ -141,6 +142,9 @@ namespace QtVsTools.Core
             {
                 StartInfo = qmakeStartInfo,
             };
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             qmakeProc.OutputDataReceived += (sender, ev) => OutMsg(ev.Data);
             qmakeProc.ErrorDataReceived += (sender, ev) => ErrMsg(ev.Data);
 
@@ -149,30 +153,37 @@ namespace QtVsTools.Core
 
         protected virtual void OutMsg(string msg)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             if (Dte != null && !string.IsNullOrEmpty(msg))
                 Messages.Print(msg);
         }
 
         protected virtual void ErrMsg(string msg)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             if (Dte != null && !string.IsNullOrEmpty(msg))
                 Messages.Print(msg);
         }
 
         protected virtual void InfoMsg(string msg)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             if (Dte != null && !string.IsNullOrEmpty(msg))
                 Messages.Print(msg);
         }
 
         protected virtual void InfoStart(Process qmakeProc)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             InfoMsg(string.Format("--- qmake({0}): started {1}",
                 qmakeProc.Id, qmakeProc.StartInfo.FileName));
         }
 
         protected virtual void InfoExit(Process qmakeProc)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             InfoMsg(string.Format("--- qmake({0}): exit code {1} ({2:0.##} msecs)\r\n",
                 qmakeProc.Id, qmakeProc.ExitCode,
                 (qmakeProc.ExitTime - qmakeProc.StartTime).TotalMilliseconds));
@@ -180,6 +191,8 @@ namespace QtVsTools.Core
 
         public virtual int Run(bool setVCVars = false)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             int exitCode = -1;
             using (var qmakeProc = CreateProcess()) {
                 try {
@@ -231,6 +244,8 @@ namespace QtVsTools.Core
 
         protected override void InfoStart(Process qmakeProc)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             base.InfoStart(qmakeProc);
             InfoMsg("--- qmake: Working Directory: " + qmakeProc.StartInfo.WorkingDirectory);
             InfoMsg("--- qmake: Arguments: " + qmakeProc.StartInfo.Arguments);
diff --git a/QtVsTools.Core/QMakeConf.cs b/QtVsTools.Core/QMakeConf.cs
index 2701772c..7ac6ccb6 100644
--- a/QtVsTools.Core/QMakeConf.cs
+++ b/QtVsTools.Core/QMakeConf.cs
@@ -26,6 +26,7 @@
 **
 ****************************************************************************/
 
+using Microsoft.VisualStudio.Shell;
 using System;
 using System.Collections;
 using System.IO;
@@ -39,6 +40,8 @@ namespace QtVsTools.Core
 
         public QMakeConf(VersionInformation versionInfo, QMakeQuery qmakeQuery = null)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             Entries = new Hashtable();
             QMakeSpecDirectory = Path.Combine(versionInfo.qtDir, "mkspecs", "default");
             var qmakeConf = Path.Combine(QMakeSpecDirectory, "qmake.conf");
diff --git a/QtVsTools.Core/QMakeQuery.cs b/QtVsTools.Core/QMakeQuery.cs
index d9007891..9e79bbea 100644
--- a/QtVsTools.Core/QMakeQuery.cs
+++ b/QtVsTools.Core/QMakeQuery.cs
@@ -30,6 +30,7 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using System.Text;
+using Microsoft.VisualStudio.Shell;
 using QtVsTools.SyntaxAnalysis;
 
 namespace QtVsTools.Core
@@ -49,6 +50,8 @@ namespace QtVsTools.Core
 
         protected override void InfoStart(Process qmakeProc)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             base.InfoStart(qmakeProc);
             InfoMsg("--- qmake: Querying persistent properties");
         }
@@ -58,6 +61,8 @@ namespace QtVsTools.Core
             stdOutput = new StringBuilder();
             Query = " ";
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (Run() == 0 && stdOutput.Length > 0) {
                 return PropertyParser
                     .Parse(stdOutput.ToString())
@@ -74,6 +79,8 @@ namespace QtVsTools.Core
         {
             get
             {
+                ThreadHelper.ThrowIfNotOnUIThread();
+
                 string value = string.Empty;
                 if (Properties.TryGetValue(name, out value))
                     return value;
@@ -83,7 +90,14 @@ namespace QtVsTools.Core
         }
 
         Dictionary<string, string> _Properties;
-        Dictionary<string, string> Properties => _Properties ?? (_Properties = QueryAllValues());
+        Dictionary<string, string> Properties
+        {
+            get
+            {
+                ThreadHelper.ThrowIfNotOnUIThread();
+                return _Properties ?? (_Properties = QueryAllValues());
+            }
+        }
 
         Parser _PropertyParser;
         Parser PropertyParser
diff --git a/QtVsTools.Core/QtModules.cs b/QtVsTools.Core/QtModules.cs
index 19bd9268..52e2fbe4 100644
--- a/QtVsTools.Core/QtModules.cs
+++ b/QtVsTools.Core/QtModules.cs
@@ -83,6 +83,8 @@ namespace QtVsTools.Core
             if (xml == null)
                 return;
 
+            Microsoft.VisualStudio.Shell.ThreadHelper.ThrowIfNotOnUIThread();
+
             foreach (var xModule in xml.Elements("QtVsTools").Elements("Module")) {
                 int id = (int)xModule.Attribute("Id");
                 QtModule module = new QtModule(id);
diff --git a/QtVsTools.Core/QtProject.cs b/QtVsTools.Core/QtProject.cs
index 5223bef7..4c651fc5 100644
--- a/QtVsTools.Core/QtProject.cs
+++ b/QtVsTools.Core/QtProject.cs
@@ -37,6 +37,7 @@ using System.Text.RegularExpressions;
 using System.Windows.Forms;
 using System.Xml;
 using QtVsTools.Core.QtMsBuild;
+using Microsoft.VisualStudio.Shell;
 
 namespace QtVsTools.Core
 {
@@ -59,6 +60,7 @@ namespace QtVsTools.Core
 
         public static QtProject Create(VCProject vcProject)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             return Create((Project)vcProject.Object);
         }
 
@@ -79,6 +81,8 @@ namespace QtVsTools.Core
 
         private QtProject(Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (project == null)
                 throw new QtVSException(SR.GetString("QtProject_CannotConstructWithoutValidProject"));
             envPro = project;
@@ -131,6 +135,8 @@ namespace QtVsTools.Core
 
         public static bool IsQtMsBuildEnabled(Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (project == null)
                 return false;
             return IsQtMsBuildEnabled(project.Object as VCProject);
@@ -139,6 +145,8 @@ namespace QtVsTools.Core
         private bool? isQtMsBuildEnabled = null;
         public bool IsQtMsBuildEnabled()
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (!isQtMsBuildEnabled.HasValue) {
                 if (vcPro != null)
                     isQtMsBuildEnabled = IsQtMsBuildEnabled(vcPro);
@@ -166,6 +174,8 @@ namespace QtVsTools.Core
         {
             get
             {
+                ThreadHelper.ThrowIfNotOnUIThread();
+
                 var ret = false;
                 if (lastConfigurationRowNames == null) {
                     lastConfigurationRowNames = envPro.ConfigurationManager.ConfigurationRowNames as Array;
@@ -187,6 +197,8 @@ namespace QtVsTools.Core
         /// <param name="uiFile">name of the ui file</param>
         public string GetUiGeneratedFileName(string uiFile)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var fi = new FileInfo(uiFile);
             var file = fi.Name;
             if (HelperFunctions.IsUicFile(file)) {
@@ -225,6 +237,8 @@ namespace QtVsTools.Core
         private string GetRelativeMocFilePath(string file, string configName = null,
                                               string platformName = null)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var fileName = GetMocFileName(file);
             if (fileName == null)
                 return null;
@@ -252,17 +266,25 @@ namespace QtVsTools.Core
 
         public static int GetFormatVersion(Project pro)
         {
-            if (pro == null)
-                return 0;
-            return GetFormatVersion(pro.Object as VCProject);
+            ThreadHelper.ThrowIfNotOnUIThread();
+            return pro == null ? 0 : GetFormatVersion(pro.Object as VCProject);
         }
 
-        public int FormatVersion { get { return GetFormatVersion(Project); } }
+        public int FormatVersion
+        {
+            get
+            {
+                ThreadHelper.ThrowIfNotOnUIThread();
+                return GetFormatVersion(Project);
+            }
+        }
 
         public static string GetPropertyValue(
             EnvDTE.Project dteProject,
             string propName)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var activeConfig = dteProject.ConfigurationManager?.ActiveConfiguration;
             if (activeConfig == null)
                 return null;
@@ -275,6 +297,8 @@ namespace QtVsTools.Core
             EnvDTE.Configuration dteConfig,
             string propName)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (dteProject == null || dteConfig == null)
                 return null;
             return GetPropertyValue(
@@ -310,6 +334,8 @@ namespace QtVsTools.Core
 
         public void AddModule(int id)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (HasModule(id))
                 return;
 
@@ -375,6 +401,8 @@ namespace QtVsTools.Core
 
         public void RemoveModule(int id)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             foreach (VCConfiguration config in (IVCCollection)vcPro.Configurations) {
                 var compiler = CompilerToolWrapper.Create(config);
                 var linker = (VCLinkerTool)((IVCCollection)config.Tools).Item("VCLinkerTool");
@@ -413,6 +441,8 @@ namespace QtVsTools.Core
 
         public void UpdateModules(VersionInformation oldVersion, VersionInformation newVersion)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             foreach (VCConfiguration config in (IVCCollection)vcPro.Configurations) {
                 var linker = (VCLinkerTool)((IVCCollection)config.Tools).Item("VCLinkerTool");
 
@@ -462,6 +492,8 @@ namespace QtVsTools.Core
 
         public bool HasModule(int id)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var foundInIncludes = false;
             var foundInLibs = false;
 
@@ -514,6 +546,8 @@ namespace QtVsTools.Core
 
         public void MarkAsDesignerPluginProject()
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             Project.Globals["IsDesignerPlugin"] = true.ToString();
             if (!Project.Globals.get_VariablePersists("IsDesignerPlugin"))
                 Project.Globals.set_VariablePersists("IsDesignerPlugin", true);
@@ -558,6 +592,8 @@ namespace QtVsTools.Core
                 return;
             }
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             CustomTool toolSettings =
                 IsQtMsBuildEnabled() ? CustomTool.MSBuildTarget : CustomTool.CustomBuildStep;
 
@@ -751,6 +787,8 @@ namespace QtVsTools.Core
 
         private string GetPCHMocOptions(VCFile file, CompilerToolWrapper compiler)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             // As .moc files are included, we should not add anything there
             if (!HelperFunctions.IsHeaderFile(file.Name))
                 return string.Empty;
@@ -777,6 +815,8 @@ namespace QtVsTools.Core
             VCFileConfiguration workFileConfig,
             VCFile mocFile)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var hasDifferentMocFilePerConfig =
                 QtVSIPSettings.HasDifferentMocFilePerConfig(envPro);
             var hasDifferentMocFilePerPlatform =
@@ -903,6 +943,9 @@ namespace QtVsTools.Core
                 + mocFileName + "))";
             var regExp = new Regex(pattern);
             var matchList = regExp.Matches(tool.Outputs.Replace(ProjectMacros.Name, baseFileName));
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (matchList.Count > 0) {
                 if (matchList[0].Length > 0)
                     outputMocFile = matchList[0].ToString();
@@ -1037,6 +1080,8 @@ namespace QtVsTools.Core
             string includes,
             string description)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var baseFileName = sourceFile.Name.Remove(sourceFile.Name.LastIndexOf('.'));
             var outputMocFile = GetRelativeMocFilePath(sourceFile.FullPath);
             var outputMocPath = Path.GetDirectoryName(outputMocFile);
@@ -1074,6 +1119,8 @@ namespace QtVsTools.Core
             var platform = vcConfig.Platform as VCPlatform;
             var platformName = platform.Name;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var mocRelPath = GetRelativeMocFilePath(
                 sourceFile.FullPath,
                 vcConfig.ConfigurationName,
@@ -1164,6 +1211,7 @@ namespace QtVsTools.Core
             CustomTool toolSettings =
                 IsQtMsBuildEnabled() ? CustomTool.MSBuildTarget : CustomTool.CustomBuildStep;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
             try {
                 var mocFileName = GetMocFileName(file.FullPath);
                 if (mocFileName == null)
@@ -1257,6 +1305,8 @@ namespace QtVsTools.Core
             if (HelperFunctions.IsHeaderFile(file.Name))
                 return CheckForCommand(file, "moc.exe");
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (HelperFunctions.IsSourceFile(file.Name)) {
                 return (HasCppMocFiles(file));
             }
@@ -1286,6 +1336,8 @@ namespace QtVsTools.Core
 
         public void RefreshRccSteps()
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             Messages.Print("\r\n=== Update rcc steps ===");
             var files = GetResourceFiles();
 
@@ -1316,6 +1368,8 @@ namespace QtVsTools.Core
 
         public void RefreshRccSteps(string oldRccDir)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             RefreshRccSteps();
             UpdateCompilerIncludePaths(oldRccDir, QtVSIPSettings.GetRccDirectory(envPro));
         }
@@ -1348,16 +1402,15 @@ namespace QtVsTools.Core
             var cmdLine = string.Empty;
 
             var cbt = HelperFunctions.GetCustomBuildTool(vfc);
-
             cbt.AdditionalDependencies = filesInQrcFile;
-
             cbt.Description = "Rcc'ing " + ProjectMacros.FileName + "...";
-
             cbt.Outputs = qrcCppFile.Replace(nameOnly, ProjectMacros.Name);
 
             cmdLine += "\"" + Resources.rcc4Command + "\""
                 + " -name \"" + ProjectMacros.Name + "\"";
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (rccOptsCfg == null)
                 rccOptsCfg = HelperFunctions.ParseRccOptions(cbt.CommandLine, qrcFile);
 
@@ -1378,6 +1431,8 @@ namespace QtVsTools.Core
                 return;
             }
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             CustomTool toolSettings =
                 IsQtMsBuildEnabled() ? CustomTool.MSBuildTarget : CustomTool.CustomBuildStep;
 
@@ -1529,27 +1584,30 @@ namespace QtVsTools.Core
 
         bool HasCppMocFiles(VCFile cppFile)
         {
-            if (!IsQtMsBuildEnabled()) {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
+            if (!IsQtMsBuildEnabled())
                 return File.Exists(Path.ChangeExtension(cppFile.FullPath, ".cbt"));
-            } else {
-                var vcProj = cppFile.project as VCProject;
-                if (vcProj != null) {
-                    foreach (VCFile vcFile in (IVCCollection)vcProj.Files) {
-                        if (vcFile.ItemType == "CustomBuild") {
-                            if (IsCppMocFileCustomBuild(vcProj, vcFile, cppFile))
-                                return true;
-                        } else if (vcFile.ItemType == QtMoc.ItemTypeName) {
-                            if (IsCppMocFileQtMsBuild(vcProj, vcFile, cppFile))
-                                return true;
-                        }
+
+            var vcProj = cppFile.project as VCProject;
+            if (vcProj != null) {
+                foreach (VCFile vcFile in (IVCCollection)vcProj.Files) {
+                    if (vcFile.ItemType == "CustomBuild") {
+                        if (IsCppMocFileCustomBuild(vcProj, vcFile, cppFile))
+                            return true;
+                    } else if (vcFile.ItemType == QtMoc.ItemTypeName) {
+                        if (IsCppMocFileQtMsBuild(vcProj, vcFile, cppFile))
+                            return true;
                     }
                 }
-                return false;
             }
+            return false;
         }
 
         public void RemoveMocStep(VCFile file)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (file.ItemType == QtMoc.ItemTypeName) {
                 RemoveMocStepQtMsBuild(file);
             } else if (HelperFunctions.IsHeaderFile(file.Name)) {
@@ -1588,6 +1646,7 @@ namespace QtVsTools.Core
         /// <param name="file">file</param>
         public void RemoveMocStepCustomBuild(VCFile file)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             try {
                 if (!HasMocStep(file))
                     return;
@@ -1971,6 +2030,8 @@ namespace QtVsTools.Core
 
         public bool IsDesignerPluginProject()
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var b = false;
             if (Project.Globals.get_VariablePersists("IsDesignerPlugin")) {
                 var s = (string)Project.Globals["IsDesignerPlugin"];
@@ -1997,7 +2058,7 @@ namespace QtVsTools.Core
             }
 
             try {
-                Microsoft.VisualStudio.Shell.ThreadHelper.ThrowIfNotOnUIThread();
+                ThreadHelper.ThrowIfNotOnUIThread();
                 var prop = dte.get_Properties("TextEditor", "C/C++");
                 var tabSize = Convert.ToInt64(prop.Item("TabSize").Value);
                 var insertTabs = Convert.ToBoolean(prop.Item("InsertTabs").Value);
@@ -2056,6 +2117,8 @@ namespace QtVsTools.Core
 
         public void AddActiveQtBuildStep(string version, string defFile = null)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (FormatVersion < Resources.qtMinFormatVersion_ClProperties)
                 return;
 
@@ -2086,6 +2149,8 @@ namespace QtVsTools.Core
 
         private void UpdateCompilerIncludePaths(string oldDir, string newDir)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var fixedOldDir = FixFilePathForComparison(oldDir);
             var dirs = new[] {
                 FixFilePathForComparison(QtVSIPSettings.GetUicDirectory(envPro)),
@@ -2139,6 +2204,8 @@ namespace QtVsTools.Core
 
         public void UpdateUicSteps(string oldUicDir, bool update_inc_path)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             Messages.Print("\r\n=== Update uic steps ===");
             var vcFilter = FindFilterFromGuid(Filters.GeneratedFiles().UniqueIdentifier);
             if (vcFilter != null) {
@@ -2253,6 +2320,8 @@ namespace QtVsTools.Core
         /// <returns></returns>
         private VCFile GetGeneratedMocFile(string fileName, VCFileConfiguration fileConfig)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (QtVSIPSettings.HasDifferentMocFilePerConfig(envPro)
                 || QtVSIPSettings.HasDifferentMocFilePerPlatform(envPro)) {
                 var projectConfig = (VCConfiguration)fileConfig.ProjectConfiguration;
@@ -2332,6 +2401,8 @@ namespace QtVsTools.Core
             if (filesCollection == null)
                 return;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             int progress = 0;
             int progressTotal = filesCollection.Count;
             var waitDialog = WaitDialog.StartWithProgress(SR.GetString("Resources_QtVsTools"),
@@ -2351,6 +2422,7 @@ namespace QtVsTools.Core
 
         public void RefreshMocStep(VCFile vcfile)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             RefreshMocStep(vcfile, true);
         }
 
@@ -2371,6 +2443,8 @@ namespace QtVsTools.Core
             if (mocCmdChecker == null)
                 mocCmdChecker = new MocCmdChecker();
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             foreach (VCFileConfiguration config in (IVCCollection)vcfile.FileConfigurations) {
                 try {
                     string commandLine = "";
@@ -2503,6 +2577,8 @@ namespace QtVsTools.Core
 
         public void OnExcludedFromBuildChanged(VCFile vcFile, VCFileConfiguration vcFileCfg)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             // Update the ExcludedFromBuild flags of the mocced file
             // according to the ExcludedFromBuild flag of the mocable source file.
             var moccedFileName = GetMocFileName(vcFile.Name);
@@ -2572,6 +2648,8 @@ namespace QtVsTools.Core
 
         public void UpdateMocSteps(string oldMocDir)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             Messages.Print("\r\n=== Update moc steps ===");
             var orgFiles = new List<VCFile>();
             var abandonedMocFiles = new List<string>();
@@ -2634,6 +2712,8 @@ namespace QtVsTools.Core
 
         private void Clean()
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var solutionConfigs = envPro.DTE.Solution.SolutionBuild.SolutionConfigurations;
             var backup = new List<KeyValuePair<SolutionContext, bool>>();
             foreach (SolutionConfiguration config in solutionConfigs) {
@@ -2688,6 +2768,8 @@ namespace QtVsTools.Core
 
         public bool isWinRT()
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             try {
                 var vcProject = Project.Object as VCProject;
                 var vcConfigs = vcProject.Configurations as IVCCollection;
@@ -2714,6 +2796,8 @@ namespace QtVsTools.Core
             if (newIsWinRt == oldIsWinRt || newIsWinRt == isWinRT())
                 return true;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var promptCaption = string.Format("Change Qt Version ({0})", Project.Name);
             var promptText = string.Format(
                 "Changing Qt version from {0} to {1}.\r\n" +
@@ -2753,6 +2837,8 @@ namespace QtVsTools.Core
             var refreshMocSteps = (vsPlatformNameNew != vsPlatformNameOld);
             var platformChanged = (vsPlatformNameNew != vsPlatformNameOld);
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             try {
                 if (platformChanged) {
                     if (!SelectSolutionPlatform(vsPlatformNameNew) || !HasPlatform(vsPlatformNameNew)) {
@@ -2804,6 +2890,8 @@ namespace QtVsTools.Core
 
         public bool SelectSolutionPlatform(string platformName)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             foreach (SolutionConfiguration solutionCfg in dte.Solution.SolutionBuild.SolutionConfigurations) {
                 var contexts = solutionCfg.SolutionContexts;
                 for (var i = 1; i <= contexts.Count; ++i) {
@@ -2829,6 +2917,8 @@ namespace QtVsTools.Core
         public void CreatePlatform(string oldPlatform, string newPlatform,
                                    VersionInformation viOld, VersionInformation viNew, ref bool newProjectCreated)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             try {
                 var cfgMgr = envPro.ConfigurationManager;
                 cfgMgr.AddPlatform(newPlatform, oldPlatform, true);
@@ -2890,9 +2980,9 @@ namespace QtVsTools.Core
             if (genVCFilter == null)
                 return;
 
-            var error = false;
-            error = DeleteFilesFromFilter(genVCFilter);
-            if (error)
+            ThreadHelper.ThrowIfNotOnUIThread();
+
+            if (DeleteFilesFromFilter(genVCFilter))
                 Messages.Print(SR.GetString("DeleteGeneratedFilesError"));
         }
 
@@ -3037,6 +3127,8 @@ namespace QtVsTools.Core
 
         public void CollapseFilter(string filterName)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var solutionExplorer = (UIHierarchy)dte.Windows.Item(Constants.vsext_wk_SProjectWindow).Object;
             if (solutionExplorer.UIHierarchyItems.Count == 0)
                 return;
@@ -3050,6 +3142,8 @@ namespace QtVsTools.Core
 
         private UIHierarchyItem FindProjectHierarchyItem(UIHierarchy hierarchy)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (hierarchy.UIHierarchyItems.Count == 0)
                 return null;
 
@@ -3065,6 +3159,8 @@ namespace QtVsTools.Core
 
         private UIHierarchyItem FindProjectHierarchyItem(UIHierarchyItem root)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             UIHierarchyItem projectItem = null;
             try {
                 if (root.Name == envPro.Name)
@@ -3085,6 +3181,7 @@ namespace QtVsTools.Core
         /// </summary>
         public string GetQtVersion()
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             return QtVersionManager.The().GetProjectQtVersion(envPro);
         }
 
@@ -3093,6 +3190,7 @@ namespace QtVsTools.Core
         /// </summary>
         public void SetQtEnvironment()
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             SetQtEnvironment(QtVersionManager.The().GetProjectQtVersion(envPro));
         }
 
@@ -3101,6 +3199,7 @@ namespace QtVsTools.Core
         /// </summary>
         public void SetQtEnvironment(string qtVersion)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             SetQtEnvironment(qtVersion, string.Empty);
         }
 
@@ -3119,6 +3218,8 @@ namespace QtVsTools.Core
             if (qtVersion != "$(QTDIR)")
                 qtDir = QtVersionManager.The().GetInstallPath(qtVersion);
             HelperFunctions.SetEnvironmentVariableEx("QTDIR", qtDir);
+
+            ThreadHelper.ThrowIfNotOnUIThread();
             try {
                 var propertyAccess = (IVCBuildPropertyStorage)vcPro;
                 var vcprj = envPro.Object as VCProject;
diff --git a/QtVsTools.Core/QtVSIPSettings.cs b/QtVsTools.Core/QtVSIPSettings.cs
index 58c7b2ad..374cfb0f 100644
--- a/QtVsTools.Core/QtVSIPSettings.cs
+++ b/QtVsTools.Core/QtVSIPSettings.cs
@@ -26,6 +26,7 @@
 **
 ****************************************************************************/
 
+using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.VCProjectEngine;
 using Microsoft.Win32;
 using System;
@@ -56,11 +57,14 @@ namespace QtVsTools.Core
 
         public static string GetUicDirectory(EnvDTE.Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             return GetDirectory(project, Resources.uicDirKeyword);
         }
 
         public static void SaveUicDirectory(EnvDTE.Project project, string directory)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (directory == null)
                 SaveDirectory(project, Resources.uicDirKeyword, GetDirectory(project, Resources.uicDirKeyword));
             else
@@ -74,6 +78,7 @@ namespace QtVsTools.Core
 
         public static string GetMocDirectory(EnvDTE.Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             return GetDirectory(project, Resources.mocDirKeyword);
         }
 
@@ -82,6 +87,8 @@ namespace QtVsTools.Core
             string configName,
             string platformName, VCFile vCFile)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             string filePath = null;
             if (vCFile != null)
                 filePath = vCFile.FullPath;
@@ -94,6 +101,8 @@ namespace QtVsTools.Core
             string platformName,
             string filePath = null)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var dir = GetDirectory(project, Resources.mocDirKeyword);
             if (!string.IsNullOrEmpty(configName)
                 && !string.IsNullOrEmpty(platformName))
@@ -103,12 +112,16 @@ namespace QtVsTools.Core
 
         public static bool HasDifferentMocFilePerConfig(EnvDTE.Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var mocDir = GetMocDirectory(project);
             return mocDir.Contains("$(ConfigurationName)");
         }
 
         public static bool HasDifferentMocFilePerPlatform(EnvDTE.Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var mocDir = GetMocDirectory(project);
             return mocDir.Contains("$(PlatformName)");
         }
@@ -120,11 +133,14 @@ namespace QtVsTools.Core
 
         public static string GetMocOptions(EnvDTE.Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             return GetOption(project, Resources.mocOptionsKeyword);
         }
 
         public static bool GetLUpdateOnBuild(EnvDTE.Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (GetProjectQtSetting(project, "QtRunLUpdateOnBuild") == "true")
                 return true;
             return GetBoolValue(project, Resources.lupdateKeyword);
@@ -137,6 +153,8 @@ namespace QtVsTools.Core
 
         static string GetProjectQtSetting(EnvDTE.Project project, string propertyName)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var vcProject = project.Object as VCProject;
             if (vcProject == null)
                 return null;
@@ -165,6 +183,8 @@ namespace QtVsTools.Core
 
         public static string GetLUpdateOptions(EnvDTE.Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             string qtLUpdateOptions = GetProjectQtSetting(project, "QtLUpdateOptions");
             if (!string.IsNullOrEmpty(qtLUpdateOptions))
                 return qtLUpdateOptions;
@@ -178,6 +198,8 @@ namespace QtVsTools.Core
 
         public static string GetLReleaseOptions(EnvDTE.Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             string qtLReleaseOptions = GetProjectQtSetting(project, "QtLReleaseOptions");
             if (!string.IsNullOrEmpty(qtLReleaseOptions))
                 return qtLReleaseOptions;
@@ -186,6 +208,8 @@ namespace QtVsTools.Core
 
         public static void SaveMocDirectory(EnvDTE.Project project, string directory)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (directory == null)
                 SaveDirectory(project, Resources.mocDirKeyword, GetDirectory(project, Resources.mocDirKeyword));
             else
@@ -196,11 +220,15 @@ namespace QtVsTools.Core
         {
             if (options == null)
                 options = GetMocOptions();
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             SaveOption(project, Resources.mocOptionsKeyword, options);
         }
 
         public static void SaveLUpdateOnBuild(EnvDTE.Project project, bool value)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             SetBoolValue(project, Resources.lupdateKeyword, value);
         }
 
@@ -209,6 +237,8 @@ namespace QtVsTools.Core
             if (options == null)
                 options = GetLUpdateOptions();
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             SaveOption(project, Resources.lupdateOptionsKeyword, options);
         }
 
@@ -216,16 +246,22 @@ namespace QtVsTools.Core
         {
             if (options == null)
                 options = GetLReleaseOptions();
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             SaveOption(project, Resources.lreleaseOptionsKeyword, options);
         }
 
         public static string GetRccDirectory(EnvDTE.Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             return GetDirectory(project, Resources.rccDirKeyword);
         }
 
         public static void SaveRccDirectory(EnvDTE.Project project, string directory)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (directory == null)
                 SaveDirectory(project, Resources.rccDirKeyword, GetDirectory(project, Resources.rccDirKeyword));
             else
@@ -272,6 +308,8 @@ namespace QtVsTools.Core
 
         private static string GetDirectory(EnvDTE.Project project, string type)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             // check for directory in following order:
             // - stored in project
             // - stored in cache
@@ -355,6 +393,8 @@ namespace QtVsTools.Core
 
         private static string GetOption(EnvDTE.Project project, string type)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             // check for directory in following order:
             // - stored in project
             // - globally defined default option
@@ -366,6 +406,8 @@ namespace QtVsTools.Core
 
         private static bool GetBoolValue(EnvDTE.Project project, string type)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             // check for directory in following order:
             // - stored in project
             // - globally defined default option
@@ -377,6 +419,8 @@ namespace QtVsTools.Core
 
         private static void SaveDirectory(EnvDTE.Project project, string type, string dir)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             dir = HelperFunctions.NormalizeRelativeFilePath(dir);
             project.Globals[type] = dir;
             if (!project.Globals.get_VariablePersists(type))
@@ -387,6 +431,8 @@ namespace QtVsTools.Core
 
         private static void SaveOption(EnvDTE.Project project, string type, string option)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             project.Globals[type] = option;
             if (!project.Globals.get_VariablePersists(type))
                 project.Globals.set_VariablePersists(type, true);
@@ -394,6 +440,8 @@ namespace QtVsTools.Core
 
         private static void SetBoolValue(EnvDTE.Project project, string type, bool value)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             project.Globals[type] = Convert.ToInt32(value).ToString();
             if (!project.Globals.get_VariablePersists(type))
                 project.Globals.set_VariablePersists(type, true);
@@ -401,6 +449,8 @@ namespace QtVsTools.Core
 
         public static void cleanUpCache(EnvDTE.Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             try {
                 var mocEnumerator = mocDirCache.GetEnumerator();
                 while (mocEnumerator.MoveNext()) {
diff --git a/QtVsTools.Core/QtVersionManager.cs b/QtVsTools.Core/QtVersionManager.cs
index c52b0661..9353efab 100644
--- a/QtVsTools.Core/QtVersionManager.cs
+++ b/QtVsTools.Core/QtVersionManager.cs
@@ -26,6 +26,7 @@
 **
 ****************************************************************************/
 
+using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.VCProjectEngine;
 using Microsoft.Win32;
 using System;
@@ -48,6 +49,8 @@ namespace QtVsTools.Core
 
         protected QtVersionManager()
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             strVersionKey = "Versions";
             regVersionPath = Resources.registryVersionPath;
             RefreshVersionNames();
@@ -63,8 +66,8 @@ namespace QtVsTools.Core
                 }
 
             } catch (Exception e) {
-                Messages.Print(
-                    e.Message + "\r\n\r\nStacktrace:\r\n" + e.StackTrace);
+                ThreadHelper.ThrowIfNotOnUIThread();
+                Messages.Print(e.Message + "\r\n\r\nStacktrace:\r\n" + e.StackTrace);
             }
         }
 
@@ -89,6 +92,8 @@ namespace QtVsTools.Core
 
         public VersionInformation GetVersionInfo(string name)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (name == "$(DefaultQtVersion)")
                 name = GetDefaultVersion();
             if (name == null)
@@ -108,6 +113,7 @@ namespace QtVsTools.Core
 
         public VersionInformation GetVersionInfo(EnvDTE.Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             return GetVersionInfo(GetProjectQtVersion(project));
         }
 
@@ -118,6 +124,8 @@ namespace QtVsTools.Core
 
         public string GetQtVersionFromInstallDir(string qtDir)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (qtDir == null)
                 return null;
 
@@ -153,6 +161,8 @@ namespace QtVsTools.Core
         /// <returns>true, if we found an invalid version</returns>
         public bool HasInvalidVersions(out string errorMessage)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var validVersions = new Dictionary<string, QtConfig>();
             var invalidVersions = new List<string>();
 
@@ -230,6 +240,8 @@ namespace QtVsTools.Core
 
         public string GetInstallPath(string version)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (version == "$(DefaultQtVersion)")
                 version = GetDefaultVersion();
             return GetInstallPath(version, Registry.CurrentUser);
@@ -237,6 +249,8 @@ namespace QtVsTools.Core
 
         public string GetInstallPath(string version, RegistryKey root)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (version == "$(DefaultQtVersion)")
                 version = GetDefaultVersion(root);
             if (version == "$(QTDIR)")
@@ -253,6 +267,8 @@ namespace QtVsTools.Core
 
         public string GetInstallPath(EnvDTE.Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var version = GetProjectQtVersion(project);
             if (version == "$(DefaultQtVersion)")
                 version = GetDefaultVersion();
@@ -283,6 +299,8 @@ namespace QtVsTools.Core
                 }
             }
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             string rootKeyPath = "SOFTWARE\\" + Resources.registryRootPath;
             string versionKeyPath = strVersionKey + "\\" + verName;
             using (var key = Registry.CurrentUser.CreateSubKey(rootKeyPath)) {
@@ -311,6 +329,9 @@ namespace QtVsTools.Core
                 return;
             key.DeleteSubKey(versionName);
             key.Close();
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             RefreshVersionNames();
         }
 
@@ -329,6 +350,7 @@ namespace QtVsTools.Core
 
         public bool SaveProjectQtVersion(EnvDTE.Project project, string version)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             return SaveProjectQtVersion(project, version, project.ConfigurationManager.ActiveConfiguration.PlatformName);
         }
 
@@ -336,6 +358,9 @@ namespace QtVsTools.Core
         {
             if (!IsVersionAvailable(version) && version != "$(DefaultQtVersion)")
                 return false;
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (QtProject.GetFormatVersion(project) >= Resources.qtMinFormatVersion_Settings) {
                 var vcPro = project.Object as VCProject;
                 if (vcPro == null)
@@ -346,6 +371,9 @@ namespace QtVsTools.Core
                 }
                 return true;
             }
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var key = "Qt5Version " + platform;
             if (!project.Globals.get_VariableExists(key) || project.Globals[key].ToString() != version)
                 project.Globals[key] = version;
@@ -356,6 +384,8 @@ namespace QtVsTools.Core
 
         public string GetProjectQtVersion(EnvDTE.Project project)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             EnvDTE.Configuration config = null;
             try {
                 config = project.ConfigurationManager.ActiveConfiguration;
@@ -383,6 +413,8 @@ namespace QtVsTools.Core
             if (QtProject.GetFormatVersion(project) >= Resources.qtMinFormatVersion_Settings)
                 return QtProject.GetPropertyValue(project, config, "QtInstall");
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var key = "Qt5Version " + config.PlatformName;
             if (!project.Globals.get_VariablePersists(key))
                 return null;
@@ -396,6 +428,8 @@ namespace QtVsTools.Core
             if (QtProject.GetFormatVersion(project) >= Resources.qtMinFormatVersion_Settings)
                 return GetProjectQtVersion(project);
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var key = "Qt5Version " + platform;
             if (!project.Globals.get_VariablePersists(key))
                 return null;
@@ -423,6 +457,9 @@ namespace QtVsTools.Core
         {
             if (!IsVersionAvailable(version) && version != "$(DefaultQtVersion)")
                 return false;
+
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             solution.Globals["Qt5Version"] = version;
             if (!solution.Globals.get_VariablePersists("Qt5Version"))
                 solution.Globals.set_VariablePersists("Qt5Version", true);
@@ -434,6 +471,8 @@ namespace QtVsTools.Core
             if (solution == null)
                 return null;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (solution.Globals.get_VariableExists("Qt5Version")) {
                 var version = (string)solution.Globals["Qt5Version"];
                 return VerifyIfQtVersionExists(version) ? version : null;
@@ -444,6 +483,7 @@ namespace QtVsTools.Core
 
         public string GetDefaultVersion()
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             return GetDefaultVersion(Registry.CurrentUser);
         }
 
@@ -458,6 +498,8 @@ namespace QtVsTools.Core
                 Messages.DisplayWarningMessage(SR.GetString("QtVersionManager_CannotLoadQtVersion"));
             }
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (defaultVersion == null) {
                 MergeVersions();
                 var key = root.OpenSubKey("SOFTWARE\\" + regVersionPath, false);
@@ -498,6 +540,8 @@ namespace QtVsTools.Core
             var hkcuVersions = GetVersions();
             var hklmVersions = GetVersions(Registry.LocalMachine);
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var hkcuInstDirs = new string[hkcuVersions.Length];
             for (var i = 0; i < hkcuVersions.Length; ++i)
                 hkcuInstDirs[i] = GetInstallPath(hkcuVersions[i]);
@@ -533,6 +577,8 @@ namespace QtVsTools.Core
 
         private bool VerifyIfQtVersionExists(string version)
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             if (version == "$(DefaultQtVersion)")
                 version = GetDefaultVersion();
             if (!string.IsNullOrEmpty(version)) {
diff --git a/QtVsTools.Core/RccOptions.cs b/QtVsTools.Core/RccOptions.cs
index 6d4696af..71c0c761 100644
--- a/QtVsTools.Core/RccOptions.cs
+++ b/QtVsTools.Core/RccOptions.cs
@@ -26,6 +26,7 @@
 **
 ****************************************************************************/
 
+using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.VCProjectEngine;
 using System;
 
@@ -57,6 +58,8 @@ namespace QtVsTools.Core
         {
             get
             {
+                ThreadHelper.ThrowIfNotOnUIThread();
+
                 if (project.Globals.get_VariablePersists("RccCompressFiles" + id)
                     && (string)project.Globals["RccCompressFiles" + id] == "true")
                     return true;
@@ -64,6 +67,8 @@ namespace QtVsTools.Core
             }
             set
             {
+                ThreadHelper.ThrowIfNotOnUIThread();
+
                 if (value)
                     project.Globals["RccCompressFiles" + id] = "true";
                 else
@@ -77,12 +82,16 @@ namespace QtVsTools.Core
         {
             get
             {
+                ThreadHelper.ThrowIfNotOnUIThread();
+
                 if (project.Globals.get_VariablePersists("RccCompressLevel" + id))
                     return Convert.ToInt32((string)project.Globals["RccCompressLevel" + id], 10);
                 return 0;
             }
             set
             {
+                ThreadHelper.ThrowIfNotOnUIThread();
+
                 project.Globals["RccCompressLevel" + id] = value.ToString();
                 if (!project.Globals.get_VariablePersists("RccCompressLevel" + id))
                     project.Globals.set_VariablePersists("RccCompressLevel" + id, true);
@@ -93,12 +102,16 @@ namespace QtVsTools.Core
         {
             get
             {
+                ThreadHelper.ThrowIfNotOnUIThread();
+
                 if (project.Globals.get_VariablePersists("RccCompressThreshold" + id))
                     return Convert.ToInt32((string)project.Globals["RccCompressThreshold" + id], 10);
                 return 0;
             }
             set
             {
+                ThreadHelper.ThrowIfNotOnUIThread();
+
                 project.Globals["RccCompressThreshold" + id] = value.ToString();
                 if (!project.Globals.get_VariablePersists("RccCompressThreshold" + id))
                     project.Globals.set_VariablePersists("RccCompressThreshold" + id, true);
diff --git a/QtVsTools.Core/VersionInformation.cs b/QtVsTools.Core/VersionInformation.cs
index a5287f8e..45129efd 100644
--- a/QtVsTools.Core/VersionInformation.cs
+++ b/QtVsTools.Core/VersionInformation.cs
@@ -26,6 +26,7 @@
 **
 ****************************************************************************/
 
+using Microsoft.VisualStudio.Shell;
 using System;
 using System.Collections;
 using System.Collections.Generic;
@@ -95,6 +96,7 @@ namespace QtVsTools.Core
         {
             qtDir = qtDirIn;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
             try {
                 var qmakeQuery = new QMakeQuery(this);
                 SetupPlatformSpecificData(qmakeQuery);
@@ -287,6 +289,8 @@ namespace QtVsTools.Core
         {
             var qmakeQuery = new QMakeQuery(this);
             string qmakeXSpec;
+
+            ThreadHelper.ThrowIfNotOnUIThread();
             try {
                 qmakeXSpec = qmakeQuery["QMAKE_XSPEC"];
             } catch {
diff --git a/QtVsTools.Core/WaitDialog.cs b/QtVsTools.Core/WaitDialog.cs
index a97a1642..0eef5bc5 100644
--- a/QtVsTools.Core/WaitDialog.cs
+++ b/QtVsTools.Core/WaitDialog.cs
@@ -28,6 +28,7 @@
 
 using System;
 using Microsoft.VisualStudio;
+using Microsoft.VisualStudio.Shell;
 using Microsoft.VisualStudio.Shell.Interop;
 using QtVsTools.VisualStudio;
 
@@ -53,6 +54,8 @@ namespace QtVsTools.Core
                 if (VsWaitDialog == null)
                     return false;
 
+                ThreadHelper.ThrowIfNotOnUIThread();
+
                 bool canceled = false;
                 int res = VsWaitDialog.HasCanceled(out canceled);
                 if (res != VSConstants.S_OK)
@@ -77,6 +80,8 @@ namespace QtVsTools.Core
                     return null;
             }
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             IVsThreadedWaitDialog2 vsWaitDialog = null;
             factory.CreateInstance(out vsWaitDialog);
             if (vsWaitDialog == null)
@@ -103,6 +108,8 @@ namespace QtVsTools.Core
             if (dialog == null)
                 return null;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var res = dialog.VsWaitDialog.StartWaitDialog(caption, message, progressText,
                     null, statusBarText, delay, isCancelable, showMarqueeProgress);
 
@@ -127,6 +134,8 @@ namespace QtVsTools.Core
             if (dialog == null)
                 return null;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             var res = dialog.VsWaitDialog.StartWaitDialogWithPercentageProgress(
                 caption, message, progressText, null, statusBarText,
                 isCancelable, delay, totalSteps, currentStep);
@@ -148,6 +157,8 @@ namespace QtVsTools.Core
             if (!Running)
                 return;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             bool canceled = false;
             int res = VsWaitDialog.UpdateProgress(message, progressText,
                 statusBarText, currentStep, totalSteps, disableCancel, out canceled);
@@ -164,6 +175,8 @@ namespace QtVsTools.Core
             if (!Running)
                 return;
 
+            ThreadHelper.ThrowIfNotOnUIThread();
+
             Running = false;
             int canceled = 0;
             VsWaitDialog.EndWaitDialog(out canceled);
@@ -172,6 +185,7 @@ namespace QtVsTools.Core
 
         void IDisposable.Dispose()
         {
+            ThreadHelper.ThrowIfNotOnUIThread();
             Stop();
         }
     }